Draft hood



W. W' EDWARDS May 11, 1954 DRAFT HOOD Filed Sept. 18, 1950 2 Sheets-Sheet l INVENTOR. 8 WA WV: Ml. [aw/mo:

May 11, 1954 w. w. EDWARDS DRAFT HOOD Filed Sept. 18, 1950 2 Sheets-Sheet 2 INVENTOR.

W4 MI: W. [amazes Patented May 11, 1954 UfilTED STATS amass ATENT OFFICE DRAFT H001) Wayne W. Edwards, Lansing, Mich, assignor to Motor Wheel Corporation, Lansing, Mich a corporation of Michigan Claims.

This invention relates to a draft hood for use on a gas burning furnace or heater.

This invention contemplates a draft hood for a gas furnace of simple structure which will effectively prevent any down draft from the stack from entering the furnace or heater and blowing out or extinguishing the burner flame or in any wise chocking or interferring with the proper combustion of the gas fuel in the combustion chamber of the furnace.

It is also an object of this invention to produce a draft hood for a gas burning furnace or heater which will maintain the proper pressure or draft in the hood so that the gas burner will burn with the proper efficiency.

In the drawings:

Fig. 1 is a top plan View showing the draft hood which is the subject of the present invention.

Fig. 2 is a rear elevation of the same.

Fig. 3 is a section along the line 3-3 of Fig. 1.

Fig. 4 is a top plan view partly broken away showing a modified form of draft hood.

Fig. 5 is a rear elevation of the same.

Fig. 6 is a section along the line 6-5 of Fig. 4.

Referring more particularly to the drawings it will be seen that the draft hood consists of a rectangular box, preferably of sheet metal, having end walls 1 and 8, top wall 9, front Wall iii and a rear wall ll. Walls 1-, 8, H] and ll are all plane walls and extend vertically. The bottom of the rectangular box is open as at l2.

The box is provided with an outlet 13 in its front wall H] which is provided with a collar 14 by means of which outlet i3 is connected into the fine or chimney. The rear wall I l of the box is provided with an inlet opening 15 which is provided with a collar it by means of which the inlet is connected with the radiator or economizer of the gas burning heater as furnace. The collar It extends or projects into the box as at ll. The extent of projection ll of collar 16 inwardly of rear wall M will vary with furnaces of different heating capacity, but as a general rule the projection ll should extend into the draft hood a distance at least of the order of about one-half inch. It should also be noted that inlet I5 is axially offset from the outlet 13. Any down draft entering the draft hood through outlet l3 will strike the opposite wall H, roll around and discharge through the open bottom l2. This down draft will be prevented from entering the inlet opening If: by the inwardly projecting annular ring or flange portion ll of collar r6. Collar projection ll also prevents any currents in the box from leaving the box by of the inlet opening it.

From the above will be noted that this draft hood is characterized by its extreme simplicity and the absence of any bafile construction within the draft hood.

The pressure head or draft in the hood is regulated by the depth of the hood below the flue outlet l3. Since the present hood has a depth below outlet l3 which will maintain a pressure head in the draft hood which is greater than allowable, the front wall It of the hood is provided with a spillway [8 in the form of a notch cut out of the lower edge of front wall Hi. It will be noted that the upper edge is of spillway 18 extends above the bottom 29 of inlet opening lii and below the bottom 2! of outlet opening l3. Spillway i3 is positioned in general below outlet opening 2! and to one side of the inlet opening l5.

The number of inlets into the draft hood will correspond to the number of outlets from the economizer or radiator. The instant draft hood can have as many inlets as desired and Figs. 4, 5 and 6 illustrate the instant draft hood with a plurality of inlets. The form of draft hood shown in Figs. 4, 5 and 6 is the same as that shown in Figs. 1 to 3 except that the hood is provided with two inlet openings 22 and 23 offset from, and positioned on opposite sides of, the outlet opening 2G. The principal form of the invention shown in Figs. 1 to 3 is for use with a furnace having one economizer or radiator whereas the draft hood shown in Figs. 4 to 6 is for use with a furnace having two economizers or radiators.

Inlet openings 22 and 23 are provided with collars 25 which are identical in structure and function to collar l6 described above. The outlet opening 2 3 is provided with a collar 26 identical in structure and function with collar 14 described above. This form of draft hood is also a rectangular box having an open bottom 21, a flat top wall 28, vertical end walls 2% and vertical front and rear walls 39 and 3!. respectively. Spillway 32 in front wall til is positioned between inlet openings 22 and 23 and beneath outlet opening 2 From the above it is evident that the instant draft hood, which is very efficient in operation, is characterized by its extremely simple structural features such as the interior flanges on the inlet openings, onset inlet and outlet openings, box-like structure with vertical walls, full bottom opening and the spillway to govern the maximum pressure head in the draft hood.

I claim:

1. A draft hood comprising a box having a closed top, a peripheral side wall and an open bottom, an outlet opening in said side wall, an inlet opening in said side wall opposite to said outlet opening, said inlet and outlet openings being ofiset from one another so that said openings are oppositely disposed in nonoverlapping relation, the portion of the side wall opposite said outlet opening being imperiorate, and a collar extending around said inlet opening on the inside of said box whereby a down draft from said outlet into said box strikes the side wall opposite said outlet and the collar shields the inlet from said down draft, said side wall comprising vertical end wall portions and vertical front and rear wall portions, said inlet opening being located in the rear wall portion and said outlet opening being located in the front wall portion, said front wall portion being provided with a spillway in the form of a cut out notch positioned below said outlet opening and offset to one side of the inlet opening.

2. The draft hood defined in claim 1 wherein the upper edge of the spillway is positioned below the outlet opening and above the lowermost point of the inlet opening,

3. The draft hood defined in claim 2 wherein the inlet opening is provided with a cylindrical collar extending exteriorially of the rear Wall portion of the box and having its axis generally perpendicular to the front wall portion of the box.

4. The draft hood defined in claim 3 wherein the collar for the inlet opening extends also interiorly of the rear wall portion of the box and is cylindrical with its axis positioned generally perpendicular to the rear wall portion of the box and offset from the axis of the outlet opening.

5. A draft hood comprising a box having a closed top, a peripheral side wall and an open bottom an outlet opening in said side wall, an inlet open ng in said side wall opposite to said outlet opening, said inlet and outlet openings being offset from one another so that said openings are oppositely disposed in nonoverlapping relation, the portion of the side wall opposite said outlet opening being imperforate, and a collar extending around said inlet opening on the inside of said box whereby a down draft from said outlet into said box strikes the side wall opposite said outlet and the collar shields the inlet from said down draft, the portion of said side wall provided with said outlet opening being prowith a spillway in the form or" a cut out notch positioned below said outlet opening and offset to one side of said inlet opening.

References Cited in the file of this patent UNITED STA'IES PATENTS Number Name Date 1,983,515 Anderson Dec. 11, 1934 2,257 240 Livar Sept. 30, 1941 2,313,933 Goerg Mar. 16, 1943 2,453,912 Higley Nov. 16, 1948 a,4o6,780 Fenberg Nov. 1, 1949 2,592,862 Coleman Apr. 15, 1952 

